CURRENT SYNOPSIS OF LATE CRETACEOUS NON-AVIAN DINOSAUR DIVERSITY IN THE SOUTHEAST

Non-avian dinosaurs are sparsely but widely distributed around the Southeastern Coastal Plain, ranging from North Carolina to Missouri. At least five new taxa, plus many new regional occurrences, have been reported in the past two decades, approximately doubling the reported diversity of known species. However, only three named regional species are based on types with sufficient cranial material to justify unique appellation; all additional references are based on fragmentary material, in several cases single teeth or bones. Nevertheless, isolated bones and teeth are often sufficiently diagnostic to justify reference to a dinosaur family or subfamily. These include the first reports of neoceratopsians in the Appalachian Cretaceous subcontinent, and the presence of several smaller theropods including velociraptorines. Many anecdotal observations, especially of amateur collections, reveal that dinosaur teeth and bones are quite common in well-known sites such as Phoebus Landing in North Carolina.

Several enduring questions about the diversity and distribution of eastern Cretaceous dinosaurs persist, including the origin, timing and means of dispersal from one side of the Cretaceous continent to the other, across the Interior Seaway. Additionally, the nature or presence of a dispersion boundary between Late Cretaceous taxa in the Northern Coastal Plain (New Jersey to Maryland) and the Southeastern Coastal Plain, is unclear: it may be an artifact of taxonomy. Further there is some asynchrony of known dinosaur occurrences in Appalachia, notably due to late Campanian and Maastrichtian deposits dominating the dinosaur record in the northern subcontinent, in contrast to Santonian and early- to mid-Campanian deposits dominating the record in the southeastern subcontinent.